There is an electric power steering apparatus including an electric motor that outputs an assist torque for the steering wheel of a vehicle and a control device that controls driving of the electric motor, in which the control device is attached to the electric motor (see, for example, PTL 1).
This electric power steering apparatus has a power circuit board on which is mounted a bridge circuit to switch a current of the electric motor, an insulating printed-circuit board on which is mounted a microcomputer that generates a drive signal to control the bridge circuit, and a large-current board on which is mounted a capacitor to absorb current ripples on conductive plates forming a large-current wiring pattern and insert-molded with insulating resin.
A control device of a triple-layer structure having the power circuit board, the large-current board, and the insulating printed-circuit board layered in this order is disposed on the electric motor and parallel to the shaft thereof. The power circuit board and the large-current board are electrically connected with a connection member.